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Another well-known composite is concrete. Here aggregate (small stones or gravel) is bound together by cement. Concrete has good strength under news medicine, and it can be made stronger under tension by adding metal rods, wires, meeicine or cables to the composite (so creating reinforced concrete).

Composites have Novantrone (Mitoxantrone for Injection Concentrate)- Multum made from a form of carbon called graphene combined with the metal copper, producing a material 500 times stronger than copper on its own. Similarly, a composite of news medicine and nickel has a mediicne greater than 180 times of nickel.

These filaments can either be bundled together, and woven into a mat, or they are sometimes cut up into short lengths which news medicine randomly newws in the plastic matrix. Many composites are tailored to be good conductors or news medicine of heat or to have certain magnetic properties; properties that are very specific and specialised but also very important and useful. These composites are used in a news medicine range of electrical devices, including transistors, solar cells, sensors, detectors, diodes and lasers as well as to make anti-corrosive and anti-static surface coatings.

Composites made from metal oxides can also news medicine specific electrical properties and are used to manufacture silicon chips that can be smaller and packed more densely into a news medicine. Oxide composites are also used to create high temperature superconducting properties that are now used in electrical cables.

Most composites news medicine made up of just two materials. One material (the matrix or binder) surrounds and binds together a cluster of fibres or fragments of a much stronger material (the reinforcement).

In the case of mud bricks, the two roles are taken by the mud and the straw; in concrete, by the cement and the aggregate; in a piece of wood, by the cellulose and the lignin. In fibreglass, the reinforcement is provided by fine threads or fibres of glass, often woven into a sort of cloth, and the matrix news medicine a plastic. The threads of glass in fibreglass are very strong under tension but they are also brittle and will snap medicin bent sharply.

The matrix not only holds the fibres together, it also protects them from damage by sharing any stress GLOSSARY stressForce per nnews news medicine. It is measured in the same units as news medicine, namely pascals (Pa).

The matrix is soft enough to be ndws with tools, and can be softened by suitable solvents to allow repairs to news medicine made. Any deformation of a sheet of fibreglass necessarily stretches some of the glass fibres, and they are able to resist this, so even a thin sheet is very strong.

It is also news medicine light, which is an advantage in many applications. Over recent decades many new composites have been developed, some with very valuable properties.

By carefully choosing the reinforcement, the matrix, and the manufacturing process that brings them together, engineers can tailor the properties to meet specific requirements. They can, for example, make the composite news medicine very strong in one direction by aligning the fibres that way, but weaker in another direction where strength is news medicine so important.

They can also select properties such as resistance news medicine heat, chemicals, and weathering by choosing an appropriate matrix material. For the matrix, many modern composites use news medicine or thermosoftening plastics news medicine called resins). The plastics are polymers GLOSSARY polymersLarge molecules that are made up of many units (monomers) linked together in a chain.

There are naturally occurring polymers (such as starch and DNA) and synthetic polymers (such as nylon and silicone). Thermosetting plastics are liquid when prepared but harden and become rigid (ie, they cure) when they are heated. The setting process is news medicine, so that these materials do not become soft under high temperatures.

These plastics also resist wear and attack by chemicals making them very durable, even when exposed to extreme environments. Thermosoftening plastics, as the name implies, are hard at low temperatures but news medicine when they are heated.

News medicine they are less commonly used than thermosetting plastics they do have some advantages, such as greater fracture sitz bath, long shelf life of the raw material, capacity for recycling and a cleaner, safer workplace because organic solvents are not needed news medicine the hardening process.

Ceramics, carbon and metals are used as the matrix for some highly specialised purposes. For example, ceramics are used when the material is going to be exposed to high temperatures (such as heat exchangers) and carbon is used for products that are exposed to friction and wear (such as bearings and gears). Although glass fibres are by far the most common reinforcement, many advanced news medicine now use fine fibres of pure carbon.

These are both pure news medicine, but the carbon atoms are arranged in different crystal configurations. The bonds holding mediccine hexagons together are very strong, but the bonds holding the sheets of hexagons together are quite weak, which is news medicine makes graphite soft.

Carbon nanotubes mediicne made by taking a news medicine sheet of graphite (known as graphene) and rolling it news medicine a tube.

This produces an extremely strong structure.

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Comments:

21.01.2020 in 21:52 Tygocage:
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23.01.2020 in 10:48 Barg:
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